diff options
Diffstat (limited to 'core/vm/gas_table.go')
| -rw-r--r-- | core/vm/gas_table.go | 441 |
1 files changed, 441 insertions, 0 deletions
diff --git a/core/vm/gas_table.go b/core/vm/gas_table.go new file mode 100644 index 0000000..2adaf85 --- /dev/null +++ b/core/vm/gas_table.go @@ -0,0 +1,441 @@ +// Copyright 2017 The go-ethereum Authors +// This file is part of the go-ethereum library. +// +// The go-ethereum library is free software: you can redistribute it and/or modify +// it under the terms of the GNU Lesser General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// The go-ethereum library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public License +// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. + +package vm + +import ( + "errors" + + "github.com/ava-labs/coreth/params" + "github.com/ava-labs/go-ethereum/common" + "github.com/ava-labs/go-ethereum/common/math" +) + +// memoryGasCost calculates the quadratic gas for memory expansion. It does so +// only for the memory region that is expanded, not the total memory. +func memoryGasCost(mem *Memory, newMemSize uint64) (uint64, error) { + if newMemSize == 0 { + return 0, nil + } + // The maximum that will fit in a uint64 is max_word_count - 1. Anything above + // that will result in an overflow. Additionally, a newMemSize which results in + // a newMemSizeWords larger than 0xFFFFFFFF will cause the square operation to + // overflow. The constant 0x1FFFFFFFE0 is the highest number that can be used + // without overflowing the gas calculation. + if newMemSize > 0x1FFFFFFFE0 { + return 0, errGasUintOverflow + } + newMemSizeWords := toWordSize(newMemSize) + newMemSize = newMemSizeWords * 32 + + if newMemSize > uint64(mem.Len()) { + square := newMemSizeWords * newMemSizeWords + linCoef := newMemSizeWords * params.MemoryGas + quadCoef := square / params.QuadCoeffDiv + newTotalFee := linCoef + quadCoef + + fee := newTotalFee - mem.lastGasCost + mem.lastGasCost = newTotalFee + + return fee, nil + } + return 0, nil +} + +// memoryCopierGas creates the gas functions for the following opcodes, and takes +// the stack position of the operand which determines the size of the data to copy +// as argument: +// CALLDATACOPY (stack position 2) +// CODECOPY (stack position 2) +// EXTCODECOPY (stack poition 3) +// RETURNDATACOPY (stack position 2) +func memoryCopierGas(stackpos int) gasFunc { + return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + // Gas for expanding the memory + gas, err := memoryGasCost(mem, memorySize) + if err != nil { + return 0, err + } + // And gas for copying data, charged per word at param.CopyGas + words, overflow := bigUint64(stack.Back(stackpos)) + if overflow { + return 0, errGasUintOverflow + } + + if words, overflow = math.SafeMul(toWordSize(words), params.CopyGas); overflow { + return 0, errGasUintOverflow + } + + if gas, overflow = math.SafeAdd(gas, words); overflow { + return 0, errGasUintOverflow + } + return gas, nil + } +} + +var ( + gasCallDataCopy = memoryCopierGas(2) + gasCodeCopy = memoryCopierGas(2) + gasExtCodeCopy = memoryCopierGas(3) + gasReturnDataCopy = memoryCopierGas(2) +) + +func gasSStore(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + var ( + y, x = stack.Back(1), stack.Back(0) + current = evm.StateDB.GetState(contract.Address(), common.BigToHash(x)) + ) + // The legacy gas metering only takes into consideration the current state + // Legacy rules should be applied if we are in Petersburg (removal of EIP-1283) + // OR Constantinople is not active + if evm.chainRules.IsPetersburg || !evm.chainRules.IsConstantinople { + // This checks for 3 scenario's and calculates gas accordingly: + // + // 1. From a zero-value address to a non-zero value (NEW VALUE) + // 2. From a non-zero value address to a zero-value address (DELETE) + // 3. From a non-zero to a non-zero (CHANGE) + switch { + case current == (common.Hash{}) && y.Sign() != 0: // 0 => non 0 + return params.SstoreSetGas, nil + case current != (common.Hash{}) && y.Sign() == 0: // non 0 => 0 + evm.StateDB.AddRefund(params.SstoreRefundGas) + return params.SstoreClearGas, nil + default: // non 0 => non 0 (or 0 => 0) + return params.SstoreResetGas, nil + } + } + // The new gas metering is based on net gas costs (EIP-1283): + // + // 1. If current value equals new value (this is a no-op), 200 gas is deducted. + // 2. If current value does not equal new value + // 2.1. If original value equals current value (this storage slot has not been changed by the current execution context) + // 2.1.1. If original value is 0, 20000 gas is deducted. + // 2.1.2. Otherwise, 5000 gas is deducted. If new value is 0, add 15000 gas to refund counter. + // 2.2. If original value does not equal current value (this storage slot is dirty), 200 gas is deducted. Apply both of the following clauses. + // 2.2.1. If original value is not 0 + // 2.2.1.1. If current value is 0 (also means that new value is not 0), remove 15000 gas from refund counter. We can prove that refund counter will never go below 0. + // 2.2.1.2. If new value is 0 (also means that current value is not 0), add 15000 gas to refund counter. + // 2.2.2. If original value equals new value (this storage slot is reset) + // 2.2.2.1. If original value is 0, add 19800 gas to refund counter. + // 2.2.2.2. Otherwise, add 4800 gas to refund counter. + value := common.BigToHash(y) + if current == value { // noop (1) + return params.NetSstoreNoopGas, nil + } + original := evm.StateDB.GetCommittedState(contract.Address(), common.BigToHash(x)) + if original == current { + if original == (common.Hash{}) { // create slot (2.1.1) + return params.NetSstoreInitGas, nil + } + if value == (common.Hash{}) { // delete slot (2.1.2b) + evm.StateDB.AddRefund(params.NetSstoreClearRefund) + } + return params.NetSstoreCleanGas, nil // write existing slot (2.1.2) + } + if original != (common.Hash{}) { + if current == (common.Hash{}) { // recreate slot (2.2.1.1) + evm.StateDB.SubRefund(params.NetSstoreClearRefund) + } else if value == (common.Hash{}) { // delete slot (2.2.1.2) + evm.StateDB.AddRefund(params.NetSstoreClearRefund) + } + } + if original == value { + if original == (common.Hash{}) { // reset to original inexistent slot (2.2.2.1) + evm.StateDB.AddRefund(params.NetSstoreResetClearRefund) + } else { // reset to original existing slot (2.2.2.2) + evm.StateDB.AddRefund(params.NetSstoreResetRefund) + } + } + return params.NetSstoreDirtyGas, nil +} + +// 0. If *gasleft* is less than or equal to 2300, fail the current call. +// 1. If current value equals new value (this is a no-op), SSTORE_NOOP_GAS gas is deducted. +// 2. If current value does not equal new value: +// 2.1. If original value equals current value (this storage slot has not been changed by the current execution context): +// 2.1.1. If original value is 0, SSTORE_INIT_GAS gas is deducted. +// 2.1.2. Otherwise, SSTORE_CLEAN_GAS gas is deducted. If new value is 0, add SSTORE_CLEAR_REFUND to refund counter. +// 2.2. If original value does not equal current value (this storage slot is dirty), SSTORE_DIRTY_GAS gas is deducted. Apply both of the following clauses: +// 2.2.1. If original value is not 0: +// 2.2.1.1. If current value is 0 (also means that new value is not 0), subtract SSTORE_CLEAR_REFUND gas from refund counter. We can prove that refund counter will never go below 0. +// 2.2.1.2. If new value is 0 (also means that current value is not 0), add SSTORE_CLEAR_REFUND gas to refund counter. +// 2.2.2. If original value equals new value (this storage slot is reset): +// 2.2.2.1. If original value is 0, add SSTORE_INIT_REFUND to refund counter. +// 2.2.2.2. Otherwise, add SSTORE_CLEAN_REFUND gas to refund counter. +func gasSStoreEIP2200(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + // If we fail the minimum gas availability invariant, fail (0) + if contract.Gas <= params.SstoreSentryGasEIP2200 { + return 0, errors.New("not enough gas for reentrancy sentry") + } + // Gas sentry honoured, do the actual gas calculation based on the stored value + var ( + y, x = stack.Back(1), stack.Back(0) + current = evm.StateDB.GetState(contract.Address(), common.BigToHash(x)) + ) + value := common.BigToHash(y) + + if current == value { // noop (1) + return params.SstoreNoopGasEIP2200, nil + } + original := evm.StateDB.GetCommittedState(contract.Address(), common.BigToHash(x)) + if original == current { + if original == (common.Hash{}) { // create slot (2.1.1) + return params.SstoreInitGasEIP2200, nil + } + if value == (common.Hash{}) { // delete slot (2.1.2b) + evm.StateDB.AddRefund(params.SstoreClearRefundEIP2200) + } + return params.SstoreCleanGasEIP2200, nil // write existing slot (2.1.2) + } + if original != (common.Hash{}) { + if current == (common.Hash{}) { // recreate slot (2.2.1.1) + evm.StateDB.SubRefund(params.SstoreClearRefundEIP2200) + } else if value == (common.Hash{}) { // delete slot (2.2.1.2) + evm.StateDB.AddRefund(params.SstoreClearRefundEIP2200) + } + } + if original == value { + if original == (common.Hash{}) { // reset to original inexistent slot (2.2.2.1) + evm.StateDB.AddRefund(params.SstoreInitRefundEIP2200) + } else { // reset to original existing slot (2.2.2.2) + evm.StateDB.AddRefund(params.SstoreCleanRefundEIP2200) + } + } + return params.SstoreDirtyGasEIP2200, nil // dirty update (2.2) +} + +func makeGasLog(n uint64) gasFunc { + return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + requestedSize, overflow := bigUint64(stack.Back(1)) + if overflow { + return 0, errGasUintOverflow + } + + gas, err := memoryGasCost(mem, memorySize) + if err != nil { + return 0, err + } + + if gas, overflow = math.SafeAdd(gas, params.LogGas); overflow { + return 0, errGasUintOverflow + } + if gas, overflow = math.SafeAdd(gas, n*params.LogTopicGas); overflow { + return 0, errGasUintOverflow + } + + var memorySizeGas uint64 + if memorySizeGas, overflow = math.SafeMul(requestedSize, params.LogDataGas); overflow { + return 0, errGasUintOverflow + } + if gas, overflow = math.SafeAdd(gas, memorySizeGas); overflow { + return 0, errGasUintOverflow + } + return gas, nil + } +} + +func gasSha3(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + gas, err := memoryGasCost(mem, memorySize) + if err != nil { + return 0, err + } + wordGas, overflow := bigUint64(stack.Back(1)) + if overflow { + return 0, errGasUintOverflow + } + if wordGas, overflow = math.SafeMul(toWordSize(wordGas), params.Sha3WordGas); overflow { + return 0, errGasUintOverflow + } + if gas, overflow = math.SafeAdd(gas, wordGas); overflow { + return 0, errGasUintOverflow + } + return gas, nil +} + +// pureMemoryGascost is used by several operations, which aside from their +// static cost have a dynamic cost which is solely based on the memory +// expansion +func pureMemoryGascost(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + return memoryGasCost(mem, memorySize) +} + +var ( + gasReturn = pureMemoryGascost + gasRevert = pureMemoryGascost + gasMLoad = pureMemoryGascost + gasMStore8 = pureMemoryGascost + gasMStore = pureMemoryGascost + gasCreate = pureMemoryGascost +) + +func gasCreate2(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + gas, err := memoryGasCost(mem, memorySize) + if err != nil { + return 0, err + } + wordGas, overflow := bigUint64(stack.Back(2)) + if overflow { + return 0, errGasUintOverflow + } + if wordGas, overflow = math.SafeMul(toWordSize(wordGas), params.Sha3WordGas); overflow { + return 0, errGasUintOverflow + } + if gas, overflow = math.SafeAdd(gas, wordGas); overflow { + return 0, errGasUintOverflow + } + return gas, nil +} + +func gasExpFrontier(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + expByteLen := uint64((stack.data[stack.len()-2].BitLen() + 7) / 8) + + var ( + gas = expByteLen * params.ExpByteFrontier // no overflow check required. Max is 256 * ExpByte gas + overflow bool + ) + if gas, overflow = math.SafeAdd(gas, params.ExpGas); overflow { + return 0, errGasUintOverflow + } + return gas, nil +} + +func gasExpEIP158(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + expByteLen := uint64((stack.data[stack.len()-2].BitLen() + 7) / 8) + + var ( + gas = expByteLen * params.ExpByteEIP158 // no overflow check required. Max is 256 * ExpByte gas + overflow bool + ) + if gas, overflow = math.SafeAdd(gas, params.ExpGas); overflow { + return 0, errGasUintOverflow + } + return gas, nil +} + +func gasCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + var ( + gas uint64 + transfersValue = stack.Back(2).Sign() != 0 + address = common.BigToAddress(stack.Back(1)) + ) + if evm.chainRules.IsEIP158 { + if transfersValue && evm.StateDB.Empty(address) { + gas += params.CallNewAccountGas + } + } else if !evm.StateDB.Exist(address) { + gas += params.CallNewAccountGas + } + if transfersValue { + gas += params.CallValueTransferGas + } + memoryGas, err := memoryGasCost(mem, memorySize) + if err != nil { + return 0, err + } + var overflow bool + if gas, overflow = math.SafeAdd(gas, memoryGas); overflow { + return 0, errGasUintOverflow + } + + evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0)) + if err != nil { + return 0, err + } + if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow { + return 0, errGasUintOverflow + } + return gas, nil +} + +func gasCallCode(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + memoryGas, err := memoryGasCost(mem, memorySize) + if err != nil { + return 0, err + } + var ( + gas uint64 + overflow bool + ) + if stack.Back(2).Sign() != 0 { + gas += params.CallValueTransferGas + } + if gas, overflow = math.SafeAdd(gas, memoryGas); overflow { + return 0, errGasUintOverflow + } + evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0)) + if err != nil { + return 0, err + } + if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow { + return 0, errGasUintOverflow + } + return gas, nil +} + +func gasDelegateCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + gas, err := memoryGasCost(mem, memorySize) + if err != nil { + return 0, err + } + evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0)) + if err != nil { + return 0, err + } + var overflow bool + if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow { + return 0, errGasUintOverflow + } + return gas, nil +} + +func gasStaticCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + gas, err := memoryGasCost(mem, memorySize) + if err != nil { + return 0, err + } + evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0)) + if err != nil { + return 0, err + } + var overflow bool + if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow { + return 0, errGasUintOverflow + } + return gas, nil +} + +func gasSelfdestruct(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { + var gas uint64 + // EIP150 homestead gas reprice fork: + if evm.chainRules.IsEIP150 { + gas = params.SelfdestructGasEIP150 + var address = common.BigToAddress(stack.Back(0)) + + if evm.chainRules.IsEIP158 { + // if empty and transfers value + if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).Sign() != 0 { + gas += params.CreateBySelfdestructGas + } + } else if !evm.StateDB.Exist(address) { + gas += params.CreateBySelfdestructGas + } + } + + if !evm.StateDB.HasSuicided(contract.Address()) { + evm.StateDB.AddRefund(params.SelfdestructRefundGas) + } + return gas, nil +} |